> You don't have that - the owner first looked up the exchange rate to US dollars
What? Any London store that accepts euros will check the rates daily to make sure they can convert back into the GBP price. Currency rates fluctuate all the time, every second of every day.
Then they aren't accepting euros as currency. At the end of the day they will immediately convert the euros to GBP.
They are willing to use euros as a medium of exchange, but only because they know they can exchange them for (to them) real currency. (Currency is relative, obviously. And just as obviously it helps that somewhere in the world there are people who use that type of money, which gives you comfort that even if you don't exchange it now, you can later.)
If this was the fate of bitcoins then it would be a failure. People may use it to send value over the internet, but no one will keep their savings in bitcoins.
To be money you have to be willing to save it. If all you do is use it as an intermediate it's not money - yet. It may eventually become money (historically intermediates often do that - especially if the conversion is difficult), but it's not money yet.
The reason it's so important for people to store the currency in savings is very simple: If no one want to keep your money long term, practically speaking there will be very little of it in circulation, which makes it hard to use.
Plenty of people save in BitCoin, some would even argue that's where much of it's value comes today. Look at the article from Richard Falkvinge that he linked to for an extreme example.
Nowhere did he suggest that the restaurant owner exchanged his BitCoins for USD. Maybe he saves them and uses them to buy something else. Who knows, maybe he buys the ingredients for his Meze using Bitcoins?
> * They are willing to use euros as a medium of exchange, but only because they know they can exchange them for (to them) real currency.*
Any person or business is only willing to use a currency as a medium of exchange because they know they can exchange them for other goods. "Currency" and "medium of exchange" aren't mutually exclusive, the former is a special form of the latter that is recognized widely (and in modern times, usually has no intrinsic value).
> * To be money you have to be willing to save it. If all you do is use it as an intermediate it's not money - yet.*
That's an insane definition for "money." You would claim that the fast food wages of a teenager who always spends it immediately is not money.
> You would claim that the fast food wages of a teenager who always spends it immediately is not money.
Just because he doesn't save it doesn't mean he's wouldn't be willing to if he had a lot of it. He isn't spending it because he thinks it doesn't keep value, he's spending it because he wants to buy things.
What? Any London store that accepts euros will check the rates daily to make sure they can convert back into the GBP price. Currency rates fluctuate all the time, every second of every day.
http://uk.finance.yahoo.com/q/bc?s=GBPEUR=X&t=1y&c=